Development of communication technology brings a massive growth in the number of terminal devices and traffic volume. The future fifth generation (5G) wireless communication protocol is aimed at enabling networked environment where data may be accessed and shared anywhere and anytime. The 5G Radio Access Technology (RAT) allows unlicensed bands to be used for more independent and flexible establishment of the network. By way of example, the unlicensed bands can be used in enterprise solutions where one company, factory or even householder establishes one network to serve private devices. Typically, the unlicensed bands are shared between networks. As a result, collision may occur if two networks are established in the same unlicensed bands.
Conventionally, the collision is handled by listen before talk (LBT) technology which monitors whether a channel is idle before data is transmitted in the channel. For example, in a Wireless Fidelity (WiFi) network operating in the unlicensed bands, when a terminal device is to transmit data, the terminal device monitors a transmission channel. If the channel is idle for a predetermined time period, the terminal device will initiate data transmission. The time period may be determined based on a Distributed Inter Frame Space (DIFS) which is specified to be 50 μs in IEEE 802.11b. If no channel is idle, the terminal device defers the transmission until a channel becomes available.
BT also applies to cellular networks where the unlicensed bands have become effective complements to licensed bands to increase network efficiency and capacity. However, when a channel is determined to be idle, the data is not transmitted immediately. Instead, the data transmission will be initiated according to the frame timing in the cellular network. If two or more terminal devices monitor the idle channel at the same time, these terminal devices will initiate the data transmission in the same frame, thereby causing collision.